Journal of Modern Physics

l-Mixing Collision in Presence of Microwave Field

Urvashi Arya, Brijender Dahiya, Vinod Prasad

Published Jan 1, 2012• 1 citation

Abstract

We have studied excitation of multilevel Na-Rydberg atom due to collision with proton in the presence of variable laser field. The interaction of laser field and Na-Rydberg atom is explored using non perturbative Floquet technique. The transition probability is calculated at different laser frequencies (GHz), projectile velocities and impact-parameter. We have also calculated total cross-section for near resonant energy transfer collision of proton with Na-Rydberg atom at different frequencies.

DOI: 10.4236/jmp.2012.31004

Related papers

Excitation of atomic hydrogen due to proton impact in the presence of a resonant laser field

Vinod Prasad, Bhupat Sharma, Man Mohan

Physica ScriptaOct 1, 19952 citations

Electron-impact excitation of atoms in the presence of a nearly resonant laser field

P. Francken, C. J. Joachain

Physical Review AApr 1, 199022 citations

Radiative Rydberg-atom–Rydberg-atom collisions in the strong-field regime

P. Pillet, Ravinder Kachru, Nam Huu Tran +2 more

Physical Review AAug 1, 198737 citations

Slow collisions of ions with Rydberg atoms

Keith B. MacAdam

Bulletin of the American Physical SocietyDec 1, 19920 citations

Electron impact excitation of the forbidden transitions in lithium and sodium atoms in the presence of a resonant laser field

R S Pundir, K. C. Mathur

Electron impact excitation of lithium (2s-3s) and sodium (3s-4s) atoms in the presence of a resonant laser field is studied. The frequency of the laser field is studied. The frequency of the laser field is chosen to match the 2s-2p (3s-3p) transition frequency in the lithium (sodium) atom. The variation of the total cross section with laser intensity and incident energy is presented.

Journal of Physics B Atomic and Molecular PhysicsFeb 14, 19857 citations

Microwave multiphoton excitation of helium Rydberg atoms: The analogy with atomic collisions

Willem van de Water, K. A. H. van Leeuwen, Suzanne Yoakum +5 more

Physical Review LettersAug 14, 198914 citations

Journal of Modern Physics

l-Mixing Collision in Presence of Microwave Field

Urvashi Arya, Brijender Dahiya, Vinod Prasad

Published Jan 1, 2012• 1 citation

Publisher

Abstract

DOI: 10.4236/jmp.2012.31004

Related papers

Excitation of atomic hydrogen due to proton impact in the presence of a resonant laser field

Vinod Prasad, Bhupat Sharma, Man Mohan

The collision of a proton with a hydrogen atom in the presence of electromagnetic radiation which is nearly resonant with the atomic levels is investigated theoretically. The non-perturbative quasi energy method is used to describe the laser-atom interaction and the proton-dressed atom collision is solved using a diagonalization technique. We have calculated the transition probabilities and the total cross-section for various transitions. We discuss the influence of various laser and collision parameters on the excitation process.The collision of a proton with a hydrogen atom in the presence of electromagnetic radiation which is nearly resonant with the atomic levels is investigated theoretically. The non-perturbative quasi energy method is used to describe the laser-atom interaction and the proton-dressed atom collision is solved using a diagonalization technique. We have calculated the transition probabilities and the total cross-section for various transitions. We discuss the influence of various laser and collision parameters on the excitation process.

Physica ScriptaOct 1, 19952 citations

Electron-impact excitation of atoms in the presence of a nearly resonant laser field

P. Francken, C. J. Joachain

We have studied the electron-impact excitation of an atom, in the presence of a laser field whose photon energy is tuned close to the energy difference between two excited final states. Both the laser-projectile and the laser-target interactions are treated nonperturbatively, while the electron-atom interaction is treated within the first Born approximation. As an application, we have analyzed the resonant laser-assisted excitation of the ${2}^{1}$ S and ${2}^{1}$ P states of helium. The agreement between the present nonperturbative results and previous perturbative ones is excellent, except for very small detunings. The present nonperturbative treatment also shows that the results given by perturbation theory on both sides of the resonance, when plotted as a function of the laser frequency, correspond to the excitation of different Floquet pseudostates. This is related to the presence of avoided crossings in the diagram of the Floquet pseudoenergies, as a function of the laser frequency.We have studied the electron-impact excitation of an atom, in the presence of a laser field whose photon energy is tuned close to the energy difference between two excited final states. Both the laser-projectile and the laser-target interactions are treated nonperturbatively, while the electron-atom interaction is treated within the first Born approximation. As an application, we have analyzed the resonant laser-assisted excitation of the ${2}^{1}$S and ${2}^{1}$P states of helium. The agreement between the present nonperturbative results and previous perturbative ones is excellent, except for very small detunings. The present nonperturbative treatment also shows that the results given by perturbation theory on both sides of the resonance, when plotted as a function of the laser frequency, correspond to the excitation of different Floquet pseudostates. This is related to the presence of avoided crossings in the diagram of the Floquet pseudoenergies, as a function of the laser frequency.

Physical Review AApr 1, 199022 citations

Radiative Rydberg-atom–Rydberg-atom collisions in the strong-field regime

P. Pillet, Ravinder Kachru, Nam Huu Tran +2 more

We describe the experimental observation of the resonant collisional energy transfer Na(ns)+Na(ns)+qh\ensuremath{\nu}\ensuremath{\rightarrow}Na(np)+Na[(n-1)p]+(q○)h\ensuremath{\nu} which occurs when the Na atoms in a strong microwave field are tuned in energy with a static field so that the energy resonance ${E}_{\mathrm{ns}}$ + ${E}_{\mathrm{ns}}$ = ${E}_{\mathrm{np}}$ +${E}_{n\mathrm{\ensuremath{-}}1}$,p\ifmmode\pm\else\textpm\fi{}mh\ensuremath{\nu} occurs. We describe our experimental observations and provide a detailed description of a nonperturbative theory which we have developed to explain our observations. The theory is essentially developed in terms of the resonant dipole-dipole collisions between ``microwave dressed'' atoms. Using an extension of the approach we used previously to describe resonant dipole-dipole collisions in the absence of microwaves, we are able to take into account all the coherences in the problem in a completely straightforward way.We describe the experimental observation of the resonant collisional energy transfer Na(ns)+Na(ns)+qh\ensuremath{\nu}\ensuremath{\rightarrow}Na(np)+Na[(n-1)p]+(q○)h\ensuremath{\nu} which occurs when the Na atoms in a strong microwave field are tuned in energy with a static field so that the energy resonance ${E}_{\mathrm{ns}}$+${E}_{\mathrm{ns}}$=${E}_{\mathrm{np}}$+${E}_{n\mathrm{\ensuremath{-}}1}$,p\ifmmode\pm\else\textpm\fi{}mh\ensuremath{\nu} occurs. We describe our experimental observations and provide a detailed description of a nonperturbative theory which we have developed to explain our observations. The theory is essentially developed in terms of the resonant dipole-dipole collisions between ``microwave dressed'' atoms. Using an extension of the approach we used previously to describe resonant dipole-dipole collisions in the absence of microwaves, we are able to take into account all the coherences in the problem in a completely straightforward way.

Physical Review AAug 1, 198737 citations

Slow collisions of ions with Rydberg atoms

Keith B. MacAdam

New experimental results have been obtained in collisions of singly charged ions with Na Rydberg atoms. (a) The distribution of final n states populated by electron capture shows non-monotonic variations of width with incident energy over the range 60-2100 eV. (b) The total capture cross section for alkali ions on Rydberg targets shows peaks and dips over the same energy range, correlated with particular reduced velocities v and the polarization of the exciting laser. (c) {ell}-Changing collision of Na{sup +} on Na(nd) targets, n=26 and 28, at low v preferentially transfer multiple units {h_bar} of orbital angular momentum under single-collision conditions, despite very large impact parameters. (d) Inelastic impacts of Na{sup f+} on Na 36s and 30p states, perturbed by electric fields, populate a strongly field-dependent mixture of nearby Stark levels. A synopsis of recent progress will be given.New experimental results have been obtained in collisions of singly charged ions with Na Rydberg atoms. (a) The distribution of final n states populated by electron capture shows non-monotonic variations of width with incident energy over the range 60-2100 eV. (b) The total capture cross section for alkali ions on Rydberg targets shows peaks and dips over the same energy range, correlated with particular reduced velocities v and the polarization of the exciting laser. (c) {ell}-Changing collision of Na{sup +} on Na(nd) targets, n=26 and 28, at low v preferentially transfer multiple units {h_bar} of orbital angular momentum under single-collision conditions, despite very large impact parameters. (d) Inelastic impacts of Na{sup f+} on Na 36s and 30p states, perturbed by electric fields, populate a strongly field-dependent mixture of nearby Stark levels. A synopsis of recent progress will be given.

Bulletin of the American Physical SocietyDec 1, 19920 citations

Electron impact excitation of the forbidden transitions in lithium and sodium atoms in the presence of a resonant laser field

R S Pundir, K. C. Mathur

Journal of Physics B Atomic and Molecular PhysicsFeb 14, 19857 citations

Microwave multiphoton excitation of helium Rydberg atoms: The analogy with atomic collisions

Willem van de Water, K. A. H. van Leeuwen, Suzanne Yoakum +5 more

We study multiphoton transitions in helium Rydberg atoms subjected to a microwave electric field of fixed frequency but varying intensity. For each principal quantum number in the range n=25--32, the ${n}^{3}$ S to ${n}^{3}$ (L>2), n=25--32, transition probability exhibits very sharp structures as a function of the field amplitude. Their positions could be reproduced precisely using a Floquet Hamiltonian for the interaction between atom and field. Their shapes are determined by the transients of field turn-on and turn-off in a way that makes a close analogy with the theory of slow atomic collisions.We study multiphoton transitions in helium Rydberg atoms subjected to a microwave electric field of fixed frequency but varying intensity. For each principal quantum number in the range n=25--32, the ${n}^{3}$S to ${n}^{3}$(L>2), n=25--32, transition probability exhibits very sharp structures as a function of the field amplitude. Their positions could be reproduced precisely using a Floquet Hamiltonian for the interaction between atom and field. Their shapes are determined by the transients of field turn-on and turn-off in a way that makes a close analogy with the theory of slow atomic collisions.

Physical Review LettersAug 14, 198914 citations

{2}^{1}

S and

{2}^{1}

P states of helium. The agreement between the present nonperturbative results and previous perturbative ones is excellent, except for very small detunings. The present nonperturbative treatment also shows that the results given by perturbation theory on both sides of the resonance, when plotted as a function of the laser frequency, correspond to the excitation of different Floquet pseudostates. This is related to the presence of avoided crossings in the diagram of the Floquet pseudoenergies, as a function of the laser frequency.

{E}_{\mathrm{ns}}

{E}_{\mathrm{ns}}

{E}_{\mathrm{np}}

+${E}_{n\mathrm{\ensuremath{-}}1}$,p\ifmmode\pm\else\textpm\fi{}mh\ensuremath{\nu} occurs. We describe our experimental observations and provide a detailed description of a nonperturbative theory which we have developed to explain our observations. The theory is essentially developed in terms of the resonant dipole-dipole collisions between ``microwave dressed'' atoms. Using an extension of the approach we used previously to describe resonant dipole-dipole collisions in the absence of microwaves, we are able to take into account all the coherences in the problem in a completely straightforward way.

We study multiphoton transitions in helium Rydberg atoms subjected to a microwave electric field of fixed frequency but varying intensity. For each principal quantum number in the range n=25--32, the

{n}^{3}

S to

{n}^{3}

(L>2), n=25--32, transition probability exhibits very sharp structures as a function of the field amplitude. Their positions could be reproduced precisely using a Floquet Hamiltonian for the interaction between atom and field. Their shapes are determined by the transients of field turn-on and turn-off in a way that makes a close analogy with the theory of slow atomic collisions.